Extracting water from manure

EAST LANSING, Michigan (AP) — A technology for extracting drinkable water from manure is on its way to commercial application this year, a U.S. university said Thursday.

The technology is particularly useful for animal operations in dry regions where water is at a premium, according to Michigan State University.

The McLanahan Nutrient Separation System is an add-on to an anaerobic digester, which extracts energy and chemicals from manure. The system adds ultrafiltration, air stripping and a reverse osmosis system to produce water that’s clean enough for cattle to drink.

The system has value both in conserving resources and protecting the environment, said Steve Safferman, an associate professor of biosystems and agricultural engineering who is working on the project.

“If you have 1,000 cows on your operation, they produce about 10 million gallons of manure a year,” Safferman said in a statement. “Here in Michigan we have a tendency to take water for granted,” said Safferman. “But out west, for example, where drought remains an issue, the accessibility of clean water could make the difference between a farm remaining viable or going out of business.”

Manure also “contains large amounts of nutrients, carbon and pathogens that can have an environmental impact if not properly managed,” said Safferman.

A particular issue is ammonia “that would otherwise be lost in the atmosphere,” said Jim Wallace, a former Michigan State student now employed by McLanahan Corp., which is working to develop the technology. “Ammonia is a negative from an air-quality standpoint.”

About 90 percent of manure is water. The system now extracts about 50 gallons of water from each 100 gallons of manure, and Wallace said developers are aiming at raising that to 65 gallons.